COMP: Remove unused variable warning.
COMP: Remove unused variable warning.

DTIPrep/src/IntensityMotionCheckPanel.cxx:358:19: warning: unused variable 'Cancel'
      [-Wunused-variable]
    QPushButton * Cancel = msgBox.addButton( tr(Cancel), QMessageBox::ActionRole);


NIRALUser/DTIPrep,juanprietob/DTIPrep,juanprietob/DTIPrep,retfurger/alpha,NIRALUser/DTIPrep,retfurger/alpha,retfurger/alpha